Use of sentinel herds to study the epidemiology of vesicular stomatitis in the state of colorado.

The research aimed to understand how vesicular stomatitis viruses (VS) endure in horses in Colorado by studying sentinel herds over a three-year period. Serological tests and environmental factors were analyzed on a quarterly basis.

Study Design and Execution

• The researchers visited 20 sentinel locations in Colorado on a quarterly basis over three years. These were selected to observe the endurance of vesicular stomatitis viruses in resident horses.
• At each visit, a comprehensive survey was conducted. It evaluated factors such as management measures, health incidents, animal movement, and environmental conditions.
• Simultaneously, clinical examinations of sentinel horses were also carried out, during which serum samples and oral swabs were collected.
• The serum samples were subjected to at least two out of four serological tests available to detect the presence of the virus.

Data Collection and Analysis

• The data was gathered and analyzed for a two-year period stretching from August 1998 to August 2000.
• The analysis of the data revealed that during the stated period there was seroconversion, which is the development of detectable antibodies in the blood directed against an infectious agent, in 1 horse for serotype New Jersey, and 8 horses for serotype Indiana. This was determined based on capture IgM tests, which are tests for specific antibodies in the blood.
• The ‘survival time’ of the horses that exhibited seroconversion was calculated using Kaplan-Meier curves. On average, horses survived around 4.17 quarters (1.04 years), although the range could extend from 1.85 quarters to 7 quarters.

Conclusions

• The results from this research suggest that vesicular stomatitis viruses could persist in the environment of the sentinel premises. This is supported by the evidence of seroconversion in horses during periods when no clinical disease was observed.